About
27
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Introduction
My research interests include how organisms adapt (or fail to adapt) to climate change. Specifically, I am interested in terrestrial plant resilience and how it interacting with animal extinctions given climate change and human activities. I use several approaches to address these questions, including field-collected pollen and other fossil records, large biodiversity databases, and mechanistic ecological models on a broad spatiotemporal scale.
Skills and Expertise
Current institution
Additional affiliations
September 2017 - July 2021
Education
September 2011 - August 2017
September 2007 - July 2011
Publications
Publications (27)
Resilient landscapes have helped maintain terrestrial biodiversity during periods of climatic and environmental change. Identifying the tempo and mode of landscape transitions and the drivers of landscape resilience are critical to maintaining natural systems and preserving biodiversity given today’s rapid climate and land use changes. However, res...
Aim
Identifying how climate change, habitat loss, and corridors interact to influence species survival or extinction is critical to understanding macro‐scale biodiversity dynamics under changing environments. In North America, the ice‐free corridor was the only major pathway for northward migration by megafaunal species during the last deglaciation...
Aim
The Bering Land Bridge ( BLB ) connected Asia and North America during glacial periods, supported a diverse ecosystem of now‐vanished megafauna, and is a proposed glacial refugium. This study tests whether southern coastal Beringia was a refugium for woody taxa during the Last Glacial Maximum ( LGM ) and hypotheses about habitats available on t...
On St. Paul Island, a remnant of the Bering Land Bridge, woolly mammoths persisted until 5,600 yr BP with no known predators or competitors, providing a natural system for studying hypothesized environmental drivers of extinction. These include overheating due to rising temperatures, starvation, and drought. Here, we test these hypotheses using Nic...
Terrestrial pollen records are abundant and widely distributed, making them an excellent proxy for past vegetation dynamics. Age-depth models relate pollen samples from sediment cores to a depositional age based on the relationship between sample depth and available chronological controls. Large-scale synthesis of pollen data benefit from consisten...
Plants will experience considerable changes in climate within their geographic ranges over the next several decades. They may respond by exhibiting niche flexibility and adapting to changing climates. Alternatively, plant taxa may exhibit climate fidelity, shifting their geographic distributions to track their preferred climates. Here, we examine t...
The late Quaternary fossil record provides crucial data that demonstrate how organisms respond to climate change. These records have been used to great effect, demonstrating that no-analog communities frequently occur during periods of no-analog climate, and that taxa demonstrate individualistic responses to change. However, our efforts to reconstr...
Significance
Mammals on landscapes within North America are now living in different climates than they did prior to major human expansions. Many smaller animals have expanded into climates now dominated by agricultural and urban regions; whereas large-bodied mammals were forced out of these climates and were relegated to colder, dryer regions. As a...
Research into global water resources is challenged by the lack of ground-based hydrometric stations and limited data sharing. It is difficult to collect good quality, long-term information about river discharges in ungauged regions. Herein, an approach was developed to determine the river discharges of 24 rivers in ungauged regions on the Tibetan P...
Human population has exponentially grown since the last glaciation, especially across temperate areas with
easy access to water sources, excluding mammal species from their former habitats. Thus, we anticipate a
change in environmental niche preferences for temperature and precipitation as increased human
population forces mammal species into more...
Human population has exponentially grown since the last glaciation, especially across temperate areas with easy access to water sources, excluding mammal species from their former habitats. Thus, we anticipate a change in environmental niche preferences for temperature and precipitation as increased human population forces mammal species into more...
Soil moisture is a core ecohydrological element in the middle–high latitude frozen area, which occupies approximately 30% of the global land area. The Sanjiang Plain, an important commercial grain production area, is the largest swampy low plain in a middle-high latitude frozen area in China. However, no published studies on this region have clarif...
Detailed multiproxy paleolimnological data from Lake Hill, St. Paul Island, Bering Sea, Alaska
Palaeoenvironmental records from the now-submerged Bering
Land Bridge (BLB) covering the Last Glacial Maximum (LGM) to the present are needed to document changing environments and connections with the dispersal of humans into North America. Moreover, terrestrially based records of environmental changes are needed in close proximity to the re-establ...
DNA metabarcoding is an increasingly popular method to characterize and quantify biodiversity in environmental samples. Metabarcoding approaches simultaneously amplify a short, variable genomic region, or “barcode,” from a broad taxonomic group via the polymerase chain reaction (PCR), using universal primers that anneal to flanking conserved region...
A phosphorus resource crisis threatens the security of global crop production, especially in developing countries like China and Brazil. Legacy phosphorus (legacy-P), which is left behind in agricultural soil by over-fertilization, can help address this issue as a new resource in the soil phosphorus pool. However, issues involved with calculating a...
Significance
St. Paul Island, Alaska, is famous for its late-surviving population of woolly mammoth. The puzzle of mid-Holocene extinction is solved via multiple independent paleoenvironmental proxies that tightly constrain the timing of extinction to 5,600 ± 100 y ago and strongly point to the effects of sea-level rise and drier climates on freshw...
Mesic tree species such as Fagus grandifolia and Tsuga canadensis experienced multiple abundance declines in eastern North America during the last 8000 years, but the causes remain unclear. This paper presents a new sub-centennial record of Holocene vegetation, fire and sedimentological changes at Spicer Lake, IN, to test hypotheses about the role...
Background/Question/Methods
In North America, more than 50% of mammal species > 32kg and all species > 1000kg were extirpated during the last deglaciation, with the latest mammoths on the mainland dating to 12,291 years BP. Hypothesized extinction drivers include climate change, vegetation change and human hunting. However, woolly mammoth (Mammuth...
Background/Question/Methods
Many paleoclimate studies have shown that the midcontinent of North America experienced a warmer and drier-than-present climate during the early and middle Holocene and relatively humid climate during the late Holocene interspersed with several centennial-scale megadroughts. In response to this climate variability, Hol...
